An extrasolar planet, or exoplanet, is a planet outside the Solar System. There are billions of stars in our galaxy and a significant percentage of these stars are likely to have planets orbiting them. There are also planets orbiting brown dwarfs and free floating planets between the stars. As of March 2010, over 400 extrasolar planets have been confirmed.

The CoRoT satellite has discovered the coolest Jupiter like exoplanet so far to pass in front of its host star, enabling detailed studies of the planet as reported by a team from Oxford University.